The adjustable crutches presently available in the market basically consist of two telescoping tubes, usually made of a metal or metal alloy, which can be secured relative to one another by means of a variety of mechanical locking mechanisms arranged at regular intervals along the tube parts. A common design of the locking devices is that both of the tube parts are provided with diametrically opposed holes which can be placed in alignment with each other, the locking taking place by inserting a pin, detend or the like through the holes in the two tubes and securing the tubes in a desired position. The purpose of the crutch adjustability in this case makes it possible for two persons of different heights to use the same crutch. A suitable crutch length can be attained for a person depending on that person's height. Once this length has been determined it is maintained until a different person uses the crutch and the length is readjusted accordingly.
These types of crutches have several disadvantages which, among other things, are related to the fact that the person is unable to change the length of the crutch during use. For example, because of the fixed crutch length, the person has very little help when sitting down, standing up, using stairs, and other similar everyday mobile activities. During these routine activities the person must rely on arm rests, chair seats, etc., for support. This can be especially difficult for older or more incapacitated persons.